WESTERN PRODUCER — Several studies assert that passive transfer of immunity is the most important factor affecting the pre-weaning health and survival of beef calves, particularly after a difficult birth.
Calves are born with an immature immune system and need the antibodies in colostrum to protect them in early life.
“If you have a dystocia such as a tough pull, take care of the passive transfer for your calf by giving colostrum. Too many of these calves will not nurse enough on their own,” said Dr. Andy Acton of Deep 小蓝视频 Animal Clinic at Ogema, Sask.
The veterinarian and beef producer said it’s important to ensure newborn calves consume colostrum within four to six hours of birth, which is key to ensuring the transfer of immunity from cow to calf.
“Any effort I expend on making sure of passive transfer, I get rewarded for with extra pounds in the fall. I don’t think there’s a cost to this, it’s just money to be made. All you need is reasonably good cows to deal with and a maternity pen,” he said.
Several factors affect the quality and amount of colostrum, including the health of the mother, her ability to produce adequate amounts of good colostrum, body condition and the nutrition she received during pregnancy.
“Then there’s the ability of the calf to absorb enough colostrum and that’s affected by its vigour,” said Acton.
Vigorous calves stand quickly and nurse two or three times in the first few hours after birth.
The calf can only absorb certain antibodies at a significant level during the first 12 hours of life, when its gut allows passage into the bloodstream. Six hours after birth, the gut begins to lose the ability to absorb these antibodies and ceases at about one day of age.
“I would rather a calf had no colostrum than a small amount at a very early age (one or two hours), unless you are going to follow up with an adequate amount before six hours of age. The gut closure process is started when they get some milk in there,” said Acton.
“To give them just a little bit and then hope they’re going to go get the rest is probably the worst thing you could do,” he said.
“I assume that the passive part of this immunity just means the calf’s immune system didn’t have to create the antibodies, but ensuring this occurs is not necessarily a passive event,” added Dr. John Campbell, professor at the University of Saskatchewan’s Western College of Veterinary Medicine.
He said failure of passive transfer, usually caused when the calf doesn’t suckle within the first four to six hours of life, means the calf is 3.2 times more likely to get sick and 5.4 times more likely to die.
Even calves that receive less than optimal amounts are 1.5 times more likely to be treated and 1.6 times more likely to die, said Campbell.
“If they went through a difficult birth, they’re not going to feel very good. They’re not going to get up and they’re not going to suck. Even if they do suck, they’re probably not going to suck enough,” said Acton.
A study by Acton and Campbell in Saskatchewan herds showed that calves with less than optimal passive transfer also weighed significantly less at weaning. It also put them at greater risk of infectious disease and death.
“We know that a calf that was assisted at birth was twice as likely to not absorb enough colostrum to have adequate positive transfer,” said Acton.
In a 2009 study by Dr. Cheryl Waldner and Dr. Leigh Rosengren, an evaluation of calves in 203 western Canadian cow-calf herds showed almost one-third of them had less than optimal levels of passive transfer.
“It is almost impossible for us to determine how much colostrum a calf has consumed when it suckles, but we can closely watch calves at birth to determine if they have suckled or not,” said Campbell.
“Ideally, we would like every calf to jump up and suckle on its own, but we need to be prepared to intervene and supplement colostrum in calves that aren’t going to do that.
“We can supplement colostrum by milking the dam and tube feeding or bottle feeding the calf, using banked colostrum from other cows on the same farm or by using one of the higher quality colostrum supplements that are available.”
Calves from assisted births and those from cows with poor udder conformation are at higher risk, as are calves from cows that lack good mothering behaviour.
“It’s just a no brainer. If you pull it, you need to tube it. If you’ve got her restrained, take the extra few minutes and do the labour of getting colostrum into that calf,” said Acton.
With twins it’s particularly important to tube both because one calf will get up first and take the best colostrum, shorting the second twin.
“The same thing with dystocia, such as a caesarean section. We almost never let one leave here that we haven’t either milked the cow and tubed the calf or given it replacement colostrum.
“And give it enough. Not one little bag, not one litre, not one small bag of Headstart. That’s not enough. You need at the very least 100 grams (of antibodies), and bigger calves should have 150 or even 200 grams, when using a replacement colostrum. That can be equivalent to 50 millilitres per kilogram of calf weight of good quality beef cow colostrum,” said Acton.
Use silicone nipples that closely resemble a mature cow’s teat.
“Once he’s got a good belly full of colostrum, you could leave him with his mother to figure out nursing for as long as a day before having to give him another feeding because he’s got his colostrum.
“If he’s a strong enough calf, you can give him the time to fumble around and find the teat. For example, if it’s a bigger teat they will figure it out. You can’t afford to leave a calf on its own in that situation unless it has had a good first feeding of colostrum.”
Suckle reflex can be gauged by rubbing two fingers along the length of the calf’s tongue and roof of the mouth. A calf with good jaw tone, good rhythm and a strong latch has a strong suckle reflex.
Campbell said a study showed that calves with a weak suckle reflex were more than 40 times more likely to not suckle the dam within four hours of birth and 6.4 times less likely to get optimal passive transfer of immunity.
“This simple test in combination with supplementing high-risk calves that experience dystocia or mismothering can help a rancher make a quick decision about colostral supplementation,” he said.
